The disclosed relates generally to micro switches, and more particularly to an optical bi-stable liquid micro switch.
Optical fibers are replacing conductive wires in telephone and data communications, since optical fibers provide extremely high bandwidth, are immune to radio frequency noise, and generate virtually no electromagnetic interference. As the cost of optical fibers decreases, use of optical fibers is expanding to applications that require switching to dynamically reconfigure the interconnection of optical signal paths.
A known approach to optical switching involves thermally controlling the presence or absence of liquid in a gap at which a plurality of optical waveguide segments or channels intersect. This approach can be implemented for example in an optical switching circuit that includes a waveguide substrate having a plurality of thermally actuated fluidic optical switches, and a heater substrate disposed adjacent the waveguide substrate. The heater substrate includes an array of heater resistors that selectively thermally actuate the optical switches, for example by forming drive bubbles to move fluid to move into and out of gaps in the waveguide substrate that transmit or reflect light as a function of the presence or absence of fluid.
Considerations with this known approach include the need for a low level constant power or frequent re-setting of the bubble states to maintain reliablity. Also, recurring xe2x80x9cbubble pinningxe2x80x9d (failure of the bubble to collapse) requires continual monitoring and active control of the substrate temperatue.
There is accordingly a need for a reliable optical switch.
The disclosed invention is directed to a thermal optical switch that includes a switch conduit comprised of a first chamber and a second chamber interconnected to the first chamber, a working fluid disposed in the switch conduit, a light diverting liquid that is immiscible with the working fluid and disposed in the switch conduit, a thermal pressure generator structure for causing the light diverting liquid to move between the first chamber and the second chamber, and a plurality of optical channels interfacing with the first chamber of the switch conduit. The state of the thermal optical switch is determined by the location of the switching liquid in the switch conduit.